Surah Al-Baqarah, verse 230

فَإِن طَلَّقَهَا فَلَا تَحِلُّ لَهُۥ مِنۢ بَعْدُ حَتَّىٰ تَنكِحَ زَوْجًا غَيْرَهُۥ ۗ فَإِن طَلَّقَهَا فَلَا جُنَاحَ عَلَيْهِمَآ أَن يَتَرَاجَعَآ إِن ظَنَّآ أَن يُقِيمَا حُدُودَ ٱللَّهِ ۗ وَتِلْكَ حُدُودُ ٱللَّهِ يُبَيِّنُهَا لِقَوْمٍ يَعْلَمُونَ ﴿٢٣٠﴾

2:230 Thereafter, if he divorces her [the third time], it is not lawful for him to remarry her until she marries another man. Should he divorce her, then there is no sin on them to return to each other, provided that they would maintain the limits ordained by Allah. These are the limits ordained by Allah, which He makes clear to people who understand